Expose Slave to instance plugins

Allow the slave object to be accessed by instance plugins through the
this.slave property.

lib/plugin.js

@@ -1,3 +1,7 @@
+/**
+ * Plugin interfaces and utilities.
+ * @module
+ */
 "use strict";
 const fs = require("fs-extra");
 const path = require("path");
@@ -9,9 +13,27 @@ const errors = require("lib/errors");
  * Base class for instance plugins
  */
 class BaseInstancePlugin {
-	constructor(info, instance) {
+	constructor(info, instance, slave) {
+		/**
+		 * The plugin's own info module
+		 */
 		this.info = info;
+
+		/**
+		 * Instance the plugin started for
+		 * @type {Instance}
+		 */
 		this.instance = instance;
+
+		/**
+		 * Slave running the instance
+		 *
+		 * With the exepction of accessing the slave's config you should
+		 * avoid ineracting with the slave object directly.
+		 *
+		 * @type {Slave}
+		 */
+		this.slave = slave;
 	}
 
 	/**

slave.js

@@ -50,7 +50,7 @@ class Instance extends link.Link{
 		});
 	}
 
-	async init(pluginInfos) {
+	async init(pluginInfos, slave) {
 		await this.server.init();
 
 		// load plugins
@@ -62,7 +62,7 @@ class Instance extends link.Link{
 			// require plugin class and initialize it
 			let pluginLoadStarted = Date.now();
 			let { InstancePlugin } = require(`./plugins/${pluginInfo.name}/${pluginInfo.instanceEntrypoint}`);
-			let instancePlugin = new InstancePlugin(pluginInfo, this);
+			let instancePlugin = new InstancePlugin(pluginInfo, this, slave);
 			await instancePlugin.init();
 			this.plugins.set(pluginInfo.name, instancePlugin);
 			plugin.attachPluginMessages(this, pluginInfo, instancePlugin);
@@ -543,7 +543,7 @@ class Slave extends link.Link {
 		let instance = new Instance(
 			connectionClient, instanceInfo.path, this.config.get("slave.factorio_directory"), instanceInfo.config
 		);
-		await instance.init(this.pluginInfos);
+		await instance.init(this.pluginInfos, this);
 
 		// XXX: race condition on multiple simultanious calls
 		this.instanceConnections.set(instanceId, instanceConnection);